Kociolek Aaron M, Tat Jimmy, Keir Peter J
Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada.
Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada.
J Biomech. 2015 Feb 5;48(3):449-55. doi: 10.1016/j.jbiomech.2014.12.029. Epub 2014 Dec 16.
Pathological changes in carpal tunnel syndrome patients include fibrosis and thickening of the subsynovial connective tissue (SSCT) adjacent to the flexor tendons in the carpal tunnel. These clinical findings suggest an etiology of excessive shear-strain force between the tendon and SSCT, underscoring the need to assess tendon gliding characteristics representative of repetitive and forceful work. A mechanical actuator moved the middle finger flexor digitorum superficialis tendon proximally and distally in eight fresh frozen cadaver arms. Eighteen experimental conditions tested the effects of three well-established biomechanical predictors of injury, including a combination of two wrist postures (0° and 30° flexion), three tendon velocities (50, 100, 150mm/sec), and three forces (10, 20, 40N). Tendon gliding resistance was determined with two light-weight load cells, and integrated over tendon displacement to represent tendon frictional work. During proximal tendon displacement, frictional work increased with tendon velocity (58.0% from 50-150mm/sec). There was a significant interaction between wrist posture and tendon force. In wrist flexion, frictional work increased 93.0% between tendon forces of 10 and 40N. In the neutral wrist posture, frictional work only increased 33.5% (from 10-40N). During distal tendon displacement, there was a similar multiplicative interaction on tendon frictional work. Concurrent exposure to multiple biomechanical work factors markedly increased tendon frictional work, thus providing a plausible link to the pathogenesis of work-related carpal tunnel syndrome. Additionally, our study provides the conceptual basis to evaluate injury risk, including the multiplicative repercussions of combined physical exposures.
腕管综合征患者的病理变化包括腕管内屈肌腱相邻的滑膜下结缔组织（SSCT）纤维化和增厚。这些临床发现提示了肌腱与SSCT之间存在过度剪切应变力的病因，强调了评估代表重复性用力工作的肌腱滑动特性的必要性。一个机械致动器在8个新鲜冷冻尸体手臂中使中指指浅屈肌腱向近端和远端移动。18种实验条件测试了三种已确定的损伤生物力学预测因素的影响，包括两种腕部姿势（0°和30°屈曲）、三种肌腱速度（50、100、150毫米/秒）和三种力（10、20、40牛）的组合。用两个轻质测力传感器确定肌腱滑动阻力，并对肌腱位移进行积分以表示肌腱摩擦功。在肌腱向近端位移期间，摩擦功随肌腱速度增加（从50至150毫米/秒增加58.0%）。腕部姿势和肌腱力之间存在显著交互作用。在腕部屈曲时，肌腱力从10牛增加到40牛时，摩擦功增加93.0%。在腕部中立姿势时，摩擦功仅增加33.5%（从10至40牛）。在肌腱向远端位移期间，对肌腱摩擦功也有类似的相乘交互作用。同时暴露于多种生物力学工作因素会显著增加肌腱摩擦功，从而为与工作相关的腕管综合征的发病机制提供了一个合理的联系。此外，我们的研究为评估损伤风险提供了概念基础，包括联合身体暴露的相乘影响。
